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1/3 of People Can't Tell 48Kbps Audio From 160Kbps

An anonymous reader writes "Results of a blind listening test show that a third of people can't tell the difference between music encoded at 48Kbps and the same music encoded at 160Kbps. The test was conducted by CNet to find out whether streaming music service Spotify sounded better than new rival Sky Songs. Spotify uses 160Kbps OGG compression for its free service, whereas Sky Songs uses 48Kbps AAC+ compression. Over a third of participants thought the lower bit rate sounded better."

12 of 567 comments (clear)

  1. Are these the same people... by N3Roaster · · Score: 4, Informative

    Are these the same people who prefer MP3 Sizzle?

    --
    Remember RFC 873!
    1. Re:Are these the same people... by -kevin- · · Score: 5, Informative

      Or maybe it seems just louder. ;)

      fyi, dynamics compression is independent of data compression

  2. I've conducted my own blind tests... by Rei · · Score: 4, Informative

    (although not as low as 46kbps) and reached the same conclusion. Most people vastly overestimate their ability to distinguish tracks encoded at different bitrates. And I've seen study after study that backs this up. This includes self-professed audiophiles, the original authors of particular tracks of music, and so forth.

    --
    Mr. Wizard... why is this place called the Cave of Hopelessness?
    1. Re:I've conducted my own blind tests... by godrik · · Score: 5, Informative

      I think it really depends on your audio setup as well. I used to have crappy speaker and could not make the difference between FLAC and low rate MP3 (I think it was fixed 128kbps).

      When I switched to better speakers then I could actually make the difference. Despite that, I am sure I won't make the difference between 192 VBR and FLAC.

      BTW, since hard drive is cheap this days, I go for FLAC for everything.

  3. In other news by Etrias · · Score: 4, Informative

    So, 1/3 of people eh? Hardly a damning assessment when your sampling size is 16 people. Besides, most people I know including myself have some sort of hearing damage from the past or don't really know what to listen for when presented with different types of sound.

  4. compared to what ? by Brigadier · · Score: 3, Informative

    I say the only valid comparison is listening to the live music, vs the digital format. This way you compare to the original and your not just saying which sounds better (which is subjective). I once worked with a audio system designer and everything was tested using analogue formats with various types of music preferably classical because of it's range in sound.

  5. Of the 16 people tested by mapkinase · · Score: 3, Informative

    "Of the 16 people tested"

    Good-bye.

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  6. Re:I have perfect codex... by Cowclops · · Score: 5, Informative

    And I've been telling people for years that the "weakest link" concept in audio reproduction is an oversimplification and therefore wrong.

    There are orthagonal distortion components introduced by various devices. An MP3's digital distortion (sizzle sounds, to borrow from another article somebody linked to) would be IN ADDITION TO poor frequency response and mechanical distortion. It isn't "masked" by it. And it doesn't take significantly more bitrate to go from "crappy" to "great." 128kbps CBR MP3 is pretty crappy, but 160kbps VBR MP3 is indistinguishable from the source "even on great systems." I don't intend to argue what bitrate you consider "sufficient," just that "Listen to a low bitrate because you have crappy speaker" implies that crappy speakers mask MP3 compression artifacts.

    If I were to go out on a limb, I'd say its possible for crappy speakers to distort even more with overcompressed MP3s than good speakers do.

  7. Re:I have perfect codex... by beelsebob · · Score: 3, Informative

    Except that most of the compression gained from mp3 is gained by removing frequencies we can't hear anyway, speakers with poor frequency response absolutely 100% do mask this.

  8. Re:Obviously, the test was flawed by iluvcapra · · Score: 5, Informative

    Jesus I'd never seen those. Just for those of you at home, I'm a professional sound designer for films, and I use ethernet cables that I bought at Fry's for a couple bucks a piece.

    But seriously, can you make a sweeping statement like "People can't tell 48k audio from 160k"

    The issue isn't "can I tell 48kbps from 160kbps" -- the real question should be: can I tell the difference between 48kbps AAC and the original uncompressed recording? AAC can sound "better" or "good" under a lot of situations where it's significantly distorting the original program material. AAC was designed specifically to choose "good sounding" over "accurate" as the bit rates get lower and lower. Also, keep in mind that a side-effect of compressing an audio stream like this is that you'll strip away noise and unusual harmonics from the original, which might cause a lower-rate recording to "sound better," when in fact stuff that the producer actually has in his mix is being removed.

    --
    Don't blame me, I voted for Baltar.
  9. Re:Did they use the mosquito sound? by StrategicIrony · · Score: 5, Informative

    it said 48Kbps, not kHZ.

    Most lossy music formats totally submarine a lot of detail at 48Kbps and I would wager that almost everyone has the auditory acuity to recognize it. They simply don't have the mental acuity to care.

    I agree, so much auto-tone (big air quotes) "music" and they hardly notice gross clipping and drastic tone flattening. :-)

  10. Apples to oranges by MoxFulder · · Score: 5, Informative

    This test isn't a complete experimental fiasco (like some of the Microsoft-sponsored listening tests that deem WMA to sound as good at 64k as MP3 at 128k).

    But there are a couple of significant flaws with it, that make the results pretty useless:

    • They used the AB method, rather than the superior ABX method. In the AB method, a participant hears the two versions of the song, without knowing which is which, and then much choose whether one is better, or whether they are equal. In the ABX method, the participant hears two distinct versions, then a third which is identical to ONE OF the first two. They are asked to figure out which of the first two samples is the same as the third. If they perform no better than chance at this task, it's a good indication that the null hypothesis may be correct. Which is very important, since modern audio codecs have gotten so good that their quality is often indistinguishable in practice. It's disingenuous to argue about slight degrees of preference without an attempt to determine their statistical significance.
    • We don't know exactly which codecs were used!!! There are many implementations of AAC+ encoders, which may differ markedly in quality (though in 2006, a credible ABX test found that none was preferred over another to a statistically significant to a 95% confidence interval). Likewise, there are multiple implementations of Ogg Vorbis encoders. The aoTuV patches, in particular, are widely considered to considerably improve sound quality.

    If you want to know about some methodologically-better comparisons of audio codec quality, please see the Codec listening test page at Wikipedia. Full disclosure: I wrote most of this article, and have attempted to compile the results of all the carefully-conducted independent tests that I could find.

    Finally, none of this is to say that we should all demand 160kbps streaming audio if 48kbps can be made to sound just as good. It's just that this study doesn't establish that, not by a long shot. The headline is also wrong in claiming that 1/3 of the participants couldn't distinguish 48k from 160k audio: in fact, they preferred the 48k audio. And preferring one format is very different from claiming that it is of a high-fidelity: for example, audio with a compressed dynamic range is by definition degraded, and yet it persists in commercial rock recordings because uniformly loud music grabs listeners' attention more easily.